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1.
孙绍晖  刘金香 《催化学报》1998,19(5):432-435
研究了反应温度,反应物浓度及空速对乙二胺在H-ZSM-5和K-ZSM-5分子筛催化剂上转化为哌嗪反应的影响。在反应温度为340℃,乙二胺浓度为50%和空速为2.3h^-1条件下,乙二胺在2.6%K-ZSM-5催化剂上的转化率为95%,哌嗪的选择性为965。  相似文献   

2.
高焕新  舒祖斌 《催化学报》1998,19(4):329-333
对钛硅分子筛TS-1催化环己酮氨氧化制环己酮肟的研究结果表明,提高催化剂的投料量、提高分子筛的钛硅比和降低H2O2的空速,有利于提高氨氧化反应的转化率和生,降低氨/酮比不利于氨氧化反应,适宜的氨/酮摩尔比应该在2.0以上,适宜的氨氧化反应温度是80℃在右,过低和过高温度都不利于氨氧化反应,进料方式会严重影响TS-1催化氨氧化反应:H2O2的连续产和氨的间歇进料方式可获得最佳的结果,在优化的反应条件  相似文献   

3.
板状镍催化剂上氨分解和氨部分氧化制氮氢气的研究   总被引:1,自引:0,他引:1  
研制了一种 Ni/Al2O3多孔板状催化剂.该催化剂在反应温度高于750℃,氨分解率高于99.5%时,允许反应空速达10000—40000h-1.用该催化板组装的反应器可采用内加热形式,和一般的外加热反应器相比可节约能耗约30%.在催化板上氨分解的经验动力学方程是γ=kp2NH3,表观活化能为153.0kJ/mol.将该催化剂用于氨部分氧化时,在空气和氨比为1.0—1.7,680—750℃,氨空速10000—40000h-1条件下,在氨点火后无外加能源情况下,能制得含氢30~43%,残氧小于0.1%的氮氢混合气,氨的转化率>99.5%,连续250小时反应表明,催化剂活性稳定.宏观动力学研究得出,反应对氨呈零级,表观活化能为37.2kJ/mol.  相似文献   

4.
赵波  梁华定  韩文锋  刘化章 《化学通报》2006,69(11):853-856
用氨合成催化剂性能评价装置,研究了反应温度、压力、空速和氢氮比对以活性炭为载体的钌基氨合成催化剂活性的影响。研究表明,低于400℃时,随着反应温度降低,催化剂的活性急剧降低。随着压力升高,催化剂活性增大。但钌催化剂具有较高的低压活性,适宜低压合成氨。随着空速的降低,催化剂的活性明显提高。在空速和压力一定的条件下,最佳氢氮比随反应温度而异,并且当空速较高或反应温度较低时,氢氮比的变化对催化剂活性的影响更加明显。  相似文献   

5.
氮化铁催化剂的制备及其苯胺催化加氢性能   总被引:4,自引:0,他引:4  
用α-Fe2O3与氨气程序升温还原方法制备出不同温度氮气的氮化铁系列催化剂。通过XRD测试对氮化过程中的晶相转变进行了分析。在中压反应装置上考察了氮化铁系列催化剂上苯胺加氢活性以及反应条件对苯胺加氢反应活性的影响。结果表明,在700℃氮化制香的氮化铁催化剂显示有较高的苯胺加氢活性,在氢压为3.0MPa,温度为250℃,n(H2)/n(oil)=18,液体空速(WHSV)为0.3h^-1时,该催化剂  相似文献   

6.
Ni系列催化剂上甲烷直接氧化制合成气   总被引:20,自引:3,他引:20  
曹立新  陈燕馨 《分子催化》1994,8(5):375-382
采用固定床流动反应装置,考察负载型Ni系列催化剂在甲烷直接氧化制合成气反应上的催化活性.空速为5.0×105h-1,CH4/O2=2条件下,不同Ni含量的催化剂中,15%Ni/Al2O3活性较好.利用TPD和XRD技术将催化剂引发温度与催化剂组成进行关联,并在700℃下考察空速对催化性能的影响.随着空速的增加,CH4的转化率增加,7.0×105h-1时达到最大,与此同时,CO的选择性一直增加.实验结果说明在非平衡体系中,CO和H2是由CH4直接转化而来,CO2是CO深度氧化的产物,在此基础上对催化剂过程的机理作了初步的探讨.  相似文献   

7.
乙二胺在ZSM-5分子筛催化剂上脱氨制哌嗪   总被引:9,自引:0,他引:9  
研究了反应温度、反应物浓度及空速对乙二胺在HZSM5和KZSM5分子筛催化剂上转化为哌嗪反应的影响.在反应温度为340℃,乙二胺浓度为50%和空速为23h-1条件下,乙二胺在26%KZSM5催化剂上的转化率为95%,哌嗪的选择性为96%.与此同时,用NH3TPD和吡啶IRTPD确定反应是在弱酸部位L酸中心上进行的,并依此推测了反应机理.  相似文献   

8.
钛硅分子筛TS-1催化环己酮氨氧化制环己酮肟   总被引:8,自引:0,他引:8  
对钛硅分子筛TS1催化环己酮氨氧化制环己酮肟的研究结果表明,提高催化剂的投料量、提高分子筛的钛硅比和降低H2O2的空速,有利于提高氨氧化反应的转化率和选择性.降低氨/酮比不利于氨氧化反应,适宜的氨/酮摩尔比应该在20以上.适宜的氨氧化反应温度是80℃左右,过低和过高的温度都不利于氨氧化反应.进料方式会严重影响TS1催化氨氧化反应:H2O2的连续进料和氨的间歇进料方式可获得最佳的结果.在优化的反应条件下,环己酮的转化率可达100%,环己酮肟的选择性为97%.给出了可能的TS1催化氨氧化反应机理,认为氨氧化反应是经历了氨催化氧化为羟胺的过程,肟是羟胺与环己酮通过非催化方式直接反应的结果.  相似文献   

9.
用自制的铁酸锌高温煤气脱硫剂研究了硫化氢浓度、硫化温度、空速对脱硫反应及脱硫剂物理性质的影响。结果表明:铁酸锌脱硫剂的反应活性随着H2S浓度及硫化温度的升高而升高,脱硫温度为550℃时,脱硫剂的硫容量最高,脱硫剂的物理性质基本保持不变;硫化空速为850h ̄(-1)时,空速和反应时间同时达到最大值。硫化反应可用未反应核收缩模型描述,得到了转化率与时间之间的动力学方程。  相似文献   

10.
高温煤气脱硫   总被引:8,自引:3,他引:8  
用自制的铁酸锌高温煤气脱硫剂研究了硫化氢浓度、硫化温度、空速对脱硫反应及脱硫剂物理性质的影响。结果表明:铁酸锌脱硫剂的反应的活性随着H2S浓度及硫化的升而而升高,脱硫温度为550℃时,脱硫剂的硫容量最高,脱硫剂的物理性质基本保持不变;硫化空速为850h^-1时,空速和反应时间同时达到最大值,硫化反应可用未反应核收缩模型描述,得到了转化率与时间之间的动力学方程  相似文献   

11.
The paper describes the kinetics of all the recorded steps of thermal decomposition of nickel sulfate hexahydrate in air. The thermal decomposition of the salt in air led to NiO at about 1060 K. The kinetic parameters, the activation energyE and the preexponential factorA, and the thermodynamic parameters, the entropy, enthalpy and free energy of activation were evaluated for the dehydration and decomposition reactions. Tentative reaction mechanisms are suggested for each step of the thermal decomposition.  相似文献   

12.
    
The effect of pre-irradiation by γ-rays (60Co) at varying dosages on subsequent thermal decomposition of differently treated samples of zinc hydroxy azide is reported here. The same kinetic forms as in the case of untreated sample, viz., the unimolecular decay law followed by the contracting cube, fit thea, t data. The rate constants increase only marginally. The effect of increasing dosage from 10 krad to 24 Mrad is very small. The effect of pre-irradiation on decomposition of the aged sample is slightly more pronounced than in the case of the fresh sample.  相似文献   

13.
Differential scanning calorimetry (DSC) was used to determine the molar enthalpies of dehydration and decomposition of CoC2O4·2H2O, Co(HCOO)2·2H2O and [Co(NH3)6]2(C2O4)3·4H2O. The first stage of dissociation of each compound is a single-step dehydration both in air and argon atmospheres. The next stages are decomposition processes influenced by experimental parameters. The enthalpies of dehydration and decomposition vary from compound to compound in each atmosphere. The obtained data have been related to the macromechanisms proposed for the thermal decomposition and the parallel-consecutive decomposition-oxidation processes. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

14.
The kinetics of manganese(II) oxalate thermal decomposition in the helium atmosphere was studied on the basis of isothermal measurements in the temperature range from 608 to 623 K. Manganese(II) oxide, MnO, was found to be the final product of reaction. The Avrami-Erofeev kinetic equation was used to describe all the experimental data in the range of decomposition degrees from 0.1 to 0.9. The determined activation energy equals 184.7 kJ mol-1 with standard deviation ±5.2 kJ mol-1. The estimated value of parameter n is 1.9 with standard deviation ±0.01 what suggests that the rate limiting step of MnC2O4 decomposition is the nucleation of new MnO phase and that the rate of nuclei growth is rising during decomposition. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

15.
本文制备了均匀棒状过氧化氢合碳酸钠,化学分析确定其组成为Na2CO3·1.5H2O2,用DTA-TG-DTG技术并辅以X-ray分析研究了它在静态空气、流动氧气和流动氮气气氛中的非等温热分解过程及动力学。  相似文献   

16.
The thermal decomposition of copper sulphate hydroxide hydrate, (CuO·CuSO4). 2Cu(OH)2·H2O, to copper oxysulphate and CuO was investigated by X-ray phase analysis, IR spectroscopy, complex thermal analysis and electron microscopy. The effect of water vapour and time of treatment on the formation of decomposition products with a large surface area is studied. The strong decrease in specific surface area of the precipitate (from 80 m2/g to 20 m2/g) thermally treated at a temperature above 250°C is associated with the elimination of water having a coordination bond with the Cu2+ ion. During this process, the interplanar distances of the crystal lattice of copper sulphate hydroxide hydrate decrease. The time of decomposition of this compound essentially affects the decrease of the specific surface area. When the decomposition proceeds in an atmosphere containing water vapour sintering processes are predominating and the phase obtained has a considerably smaller specific surface area than in cases of decomposition under dry air.  相似文献   

17.
The isothermal decomposition of zinc hydroxy azides, Zn(OH)2-x(N3)x: follows deceleratory kinetics throughout the temperature range studied. The initial part of the decomposition fits into unimolecular decay law, log (1-a) = -kt. The contracting volume law satisfactorily describes the data at higher degrees of decomposition. The maximum value ofa upto which the slow decomposition could be recorded was 0.75. The aged form of zinc hydroxy azide decomposes with much lower rates and slightly different topochemical characteristics. The decrease in the rate of decomposition on ageing has been attributed to the formation of carbonate on the surface of the compound during storage. The change in topochemical behaviour is traced to the reported layer structure of zinc hydroxy azide. The effect of pre-heating on subsequent thermal decomposition has also been discussed.  相似文献   

18.
本文报道了三苯基氧化膦与氯金酸形成的配合物 HAu Cl4.H2 O.4(C6H5) 3 PO的非等温热分解动力学 ,采用微分与积分相结合的方法 ,推断出了它的热分解反应机理 ,其热分解动力学方程为 :dα/dt=AΦe-E/ RT(32 ) (1 α) ( 2 / 3 ) [(1 α) ( 1 / 3 ) - 1 ] -1  相似文献   

19.
采用谱学和X射线单晶衍射技术, 分别对四苯基铁杂环戊二烯羰基铁配合物(μ2, η4-C4Ph4)Fe2(CO)6(1)和四苯基取代环戊二烯酮(Ph4C4CO)(2)的晶体结构进行了分析和表征。在太阳光和氙灯光(带有4种滤光片)的照射下, 利用红外吸收光谱, 详细地考察了配合物1的光分解过程和分解产物。实验结果表明, 配合物1的光分解速率与光源和波长有关, 太阳光的光解速率最快;在同一氙灯光源下, 全波长滤光片(320~780 nm)的光解速率最快。本文还对配合物1的热分解和溴分解反应进行了对比研究, 结果证实, 3种分解反应的主要产物均为配体2。  相似文献   

20.
采用谱学和X射线单晶衍射技术,分别对四苯基铁杂环戊二烯羰基铁配合物(μ2, η4-C4Ph4)Fe2(CO)6(1)和四苯基取代环戊二烯酮(Ph4C4CO)(2)的晶体结构进行了分析和表征。在太阳光和氙灯光(带有4种滤光片)的照射下,利用红外吸收光谱,详细地考察了配合物1的光分解过程和分解产物。实验结果表明,配合物1的光分解速率与光源和波长有关,太阳光的光解速率最快;在同一氙灯光源下,全波长滤光片(320~780 nm)的光解速率最快。本文还对配合物1的热分解和溴分解反应进行了对比研究,结果证实,3种分解反应的主要产物均为配体2。  相似文献   

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